Why did the government send a SWAT team after Khairullozhon Matanov?

Last Friday, Quincy resident Khairullozhon Matanov was arrested at his apartment by a SWAT team and several FBI agents as part of the Boston Marathon bombing investigation. According to The Boston Globe:

Matanov was charged with obstruction of justice by destruction, alteration, and falsification of records or documents in a federal investigation, which carries a punishment of up to 20 years in prison. He was also charged with three counts of making false statements to agents in a terrorism investigation, each of which carries a punishment of up to eight years in prison.

Matanov, a friend of the Tsarnaevs, is accused of lying to investigators and deleting files from his computer. There are no allegations that he played a role in the bombing.

The government had been conducting aerial surveillance of Matanov since shortly after the bombing and had interviewed him a number of times over the past year before deciding to charge him.

One interesting aspect of this story that hasn't gotten enough attention is the government's decision to conduct a forced-entry raid on Matanov's home when they arrested him. As Kade Crockford of the Privacy SOS blog writes, "The FBI spent considerable resources monitoring Matanov from the sky and physically at his apartment for over a year, but despite officials’ familiarity with him and his home, they sent a SWAT team to break down his door at four in the morning to arrest him."

The crimes Matanov is accused of are all nonviolent. Even if Matanov lied to investigators and deleted relevant information from his computer, it sounds as though he was otherwise cooperative, so what was the point of breaking down his door at 4 A.M. and freaking out his neighbors?

Was it to intimidate Matanov? Or was it a piece of theater to make Matanov seem scarier to the public than he really is?